Structure of origin DNA melting and unwinding complexes of a viral replication protein

乳头瘤病毒是一类重要的动物和人类致病生物。牛乳头瘤病毒（BPV-1）是该群体的典型，其疾病后果（对哺乳、挤奶和面包的干扰）在世界范围内具有重大的经济影响。高度相关的人类病毒（HPV）导致癌症，因此也对生活质量产生负面影响。由于病毒复制蛋白是重要的治疗靶点，因此病毒复制的机制引起了人们的极大兴趣。无论是病毒还是人，生物体的生存和延续都需要其遗传物质——DNA的复制，而这是由专门的蛋白质完成的。这个过程的第一个重要步骤是识别特定的“DNA复制起源”，由蛋白质分离，或“融化”，原本成对的两条DNA链（“DNA双螺旋”）。在像人类这样的高等生物中，这种“起始”事件的时间和物理精度对于避免任何遗传物质损失（例如癌症）可能导致的灾难性后果至关重要。在DNA的初始熔化后，两个螺旋DNA链的完全分离是由“解旋酶”蛋白完成的。在像病毒这样的简单生物和像人类这样的高等物种中，引发剂和解旋酶蛋白对DNA链的分离通常知之甚少。然而，这个过程似乎是高度保守的，这表明在所有系统中机制可能大致相似。我们在此建议探索和表征BPV-1中的这些复制过程。其优点是所有的病毒DNA复制活动都是由一种叫做E1的蛋白质完成的，因此简化了研究。我们将使用强大的显微镜来拍摄过程和生化技术的不同步骤的快照，这将有助于定义机制。因此，这些研究将显著有助于了解作为重要治疗靶点的乳头瘤病毒复制蛋白。在这个简化的病毒系统中对这些复制事件进行建模也将有助于我们理解人类的复制过程。因此，这些研究将有助于疾病管理和改善人类和动物健康。

The papillomaviruses are an important class of disease causing organism in animals and man. Bovine papillomavirus (BPV-1) is the model of the group and the consequences of disease (interference with suckling, milking and breading), has a significant economic impact worldwide. The highly related human viruses (HPV) cause cancer and therefore also have a negative impact on quality of life. The mechanisms of viral replication are consequently of significant interest as the viral replication proteins are important therapeutic targets. The survival and continuity of an organism, be it a virus or man, requires duplication of its genetic material- its DNA- and this is performed by specialized proteins. The first important step in this process is the recognition of specific 'origins of DNA replication' by proteins that separate, or "melt", the two otherwise paired strands of the DNA ('the DNA double helix'). In higher organisms like man, the timing and physical precision of this 'initiation' event is crucial to avoid the catastrophic consequences that may result from any loss of genetic material (for example, cancer). After the initial melting of the DNA at localized site, complete separation of the two helical DNA strands is performed by 'helicase' proteins. DNA strand separation by initiator and helicase proteins is generally poorly understood in simple organisms like viruses as well as higher species like man. However, the process appears to be highly conserved, suggesting that mechanism may be generally similar in all systems. We propose here to explore and characterize these replication processes in BPV-1. The advantage is that all the viral DNA replication activities are performed by a single protein called E1, thus simplifying the study. We will use powerful microscopes to take snapshots of different steps of the process and biochemical techniques that will help to define mechanisms. These studies will therefore contribute significantly to the understanding of the papillomavirus replication protein that is an important therapeutic target. Modeling these replication events in this simplified viral system will also help us understand the process in man. These studies will therefore assist in disease management and improving human and animal health.